SELINA LABS
SURFACE 04LIVE IN PRODUCTION LIVE

FoldSend

End-to-end encrypted file transfer with no server-side visibility. Files encrypt on the device before they leave it, keys are derived from a passphrase we never receive, and deletion destroys the key rather than chasing copies. Standalone as FoldSend, embedded in Selina.ai as Selina Send.

SHE NARRATES THIS SURFACE
CLIENT-SIDE ENCRYPTIONENFORCED
SERVER VISIBILITYNONE
PASSPHRASE TRANSMITTEDNEVER
DELETION MODELCRYPTO-SHRED
STRATUM 00TRUST MODEL ACTIVE

If we can read it, it was never private.

Most transfer services encrypt in flight and at rest. That protects the data from everyone except the service holding it, which is precisely the party you were asked to trust in the first place. The guarantee is real but it is a guarantee about our conduct, not about mathematics.

FoldSend removes the service from the trust model entirely. Encryption happens client side. The key derives from a passphrase that is never transmitted. The ciphertext we hold is inert without it, and no subpoena, breach or internal decision changes that, because the missing piece was never in our possession.

The tradeoff is honest and worth stating: lose the passphrase and the data is gone. We cannot recover it, which is the same property that makes the guarantee worth anything.

SHRED

Key destroyed, ciphertext decaying to noise. Illustrative.

STRATUM 01TRANSFER PATH ACTIVE
TRANSFER LOGSYNTHETIC
01DERIVEKey derived on device from a passphrase using a high-iteration KDF.
02SEALAuthenticated encryption applied locally before any byte is transmitted.
03TRANSMITCiphertext streamed over TLS. The server observes an opaque object.
04BOUNDExpiry window and download cap attached to the share target.
05OPENRecipient decrypts locally. The passphrase travels out of band.
06SHREDKey destroyed on deletion or expiry. Remaining bytes are permanently inert.
STRATUM 02CAPABILITY MATRIX ACTIVE

01

Encrypted in the browser

Files are encrypted on the device before transfer begins. What crosses the network is already ciphertext, and what we receive was never anything else.

02

Zero knowledge

The passphrase never reaches the servers. We store scrambled bytes with no means to interpret them, which makes the privacy claim structural rather than procedural.

03

Large file capable

Streams multi-gigabyte transfers without degrading into a queue, a chunked mess or a silent failure at the ninety percent mark.

04

Expiring access

Share targets carry download limits and expiry windows. Access is a bounded window rather than a permanent artifact loose on the internet.

05

Crypto-shred deletion

Deletion destroys the key. Cleared means cryptographically unrecoverable, consistent with every other system we build.

06

Integrity verified

Authenticated encryption means tampering is detectable, not merely unlikely. A modified object fails to open rather than opening wrong.

07

No account required to receive

A recipient needs the link and the passphrase, not a relationship with us. Fewer accounts is less surface.

08

Metadata minimized

We retain what operating the service requires and nothing that would reconstruct who sent what to whom.

09

Embedded as Selina Send

The same transfer engine is ported into the Selina.ai platform, where every user gets it as a native capability.

9 CAPABILITIESZERO KNOWLEDGEAEADCRYPTO-SHRED
STRATUM 03TECHNICAL SHAPE ACTIVE
01ENCRYPTIONClient-side authenticated encryption performed in the browser prior to upload.
02KEY DERIVATIONDerived from a user passphrase that is never transmitted or stored.
03SERVER VISIBILITYNone. Stored objects are scrambled bytes without interpretable structure.
04INTEGRITYTampering is detectable. A modified object fails to open rather than opening incorrectly.
05ACCESS CONTROLPer-link download limits and expiry windows.
06DELETIONCrypto-shred, consistent with the platform key destruction model.
07RECOVERYNone by design. A lost passphrase is unrecoverable, which is the point.
08DEPLOYMENTStandalone service and embedded platform capability, sharing one engine.
STRATUM 04DOMAIN ACTIVE
/ end-to-end encryption/ zero-knowledge architecture/ client-side key derivation/ authenticated encryption/ streaming transfer/ integrity verification/ expiring share links/ download capping/ crypto-shredding/ metadata minimization/ browser cryptography
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